UPDATE: The wave-framed bridge design was created by Miguel Rosales and the German structural engineering firm Schlaich Bergermann and Partners working collaboratively. I've changed the text below to give Schlaich Bergermann full credit.

Dapper in a dark suit and sweater and looking almost boyishly handsome though he's in his late 40s, Miguel Rosales disarmed a crowd of planners, designers and policy wonks with his presentation of the various options under consideration for the new light rail/pedestrian bridge across the Willamette River. The slides and lecture took place in Jimmy Mak's jazz club Monday night, moderated by Randy Gragg (ex-architecture columnist for The Oregonian, current editor of Portland Spaces magazine). It was a joint City Club-Bright City Lights series production. Rosales was born in Guatemala and educated in architecture at MIT, and he's spent most of his career working on bridges. Which means he's used to making presentations to the public, because the public is almost always footing the bill for bridges.

It's likely that we're going to be talking about bridges a lot in the next several years, and Rosales will be right in the middle of it, because this bridge is likely to land first and it will be prominent, sitting between the Ross Island Bridge and the Marquam Bridge, the gateway to OHSU's proposed campus expansion in the South Waterfront District. That means we are likely to load up all our anxieties about cost, effectiveness and what constitutes "good design" on it. I won't go into great detail about the presentation here, because Rosales really didn't break much new ground, but I have been thinking and talking to people about it a lot lately, and I'll get back with my own take a little later.

Rosales discussed some of his previous bridges, specifically the Zahim Bunker Hill Bridge in Boston and the Liberty Bridge in Greenville, South Carolina, the first at 10 lanes the widest cable-stayed bridge in the world and the second a much more modest pedestrian bridge that dances across a park. And then he moved on to a discussion of the two main proposals for the Willamette bridge -- another cable-stayed bridge and his brand new "wave" design structure, which he designed with the German structural engineering firm Schlaich Bergermann and Partners.

Rosales + PartnersMiguel Rosales' wave-frame bridge

For our purposes here, we'll just say that he described them both even-handedly, and then at the end, moderator Randy Gragg managed to coax him into admitting his preference for the wave design, even thought it could end up costing more, possibly much more. He likes the way the wave fits with the rest of Portland's Willamette bridges, thinks the scale of it is right (it's much smaller than the cable-stayed design) and it's unique. The cable-stayed proposal is more aggressive and monumental, and though there's nothing even remotely like in Portland today, these striking bridges have become very popular around the world. The Millau Viaduct in France, for example, is the tallest vehicular bridge in the world. (The French love records, Rosales observed.)

The other point to make is simply Rosales' commitment to the public process. "Community support is very important," he said. "It's important to relate and work with the community because it has a direct result on the design." Rosales has two things working in his favor in this. The first is that he is charmingly candid: He will be in the middle of a straightforward discussion, and suddenly roll his eyes at a slide of the new Sauvie Island bridge, for example, and say, "From a long distance, maybe it's OK." And then conclude his criticism of its lack of detailing by asking, "Was that reviewed by anybody." Apparently not the right people. He was full of praise for our bridges generally, but the Marquam Bridge received several stab wounds: "You are stuck with it for at least 50 or 60 more years."

Rosales + PartnersMiguel Rosales' stayed-cable bridge proposal

His second weapon is knowledge. He has a precise, minute understanding of bridges, not just their design but also their engineering. He knows their technological history, he knows the current examples, he knows the success and the failures. A bridge civilian leaves thinking that it's a good idea Rosales is on the case. And that's the best sort of persuasion of all.